1. Field of the Invention
The present invention relates to a novel protein which induces pollenosis and to a process for producing the same, as well as to uses thereof as a desensitizing agent for treating, preventing and/or diagnosing pollenosis.
2. Description of the Prior Art
For more than ten years, the number of patients who complain about rhinitis and conjunctivitis due to pollenosis in early spring, has been increasing in Japan. Pollenosis frequently receives much publicity from the press because the number of cases of pollenosis is significantly increasing and because it occurs in early spring at which a variety of events, festivals and the like are held. Therefore, pollenosis has become a problem of public health which could not be ignored.
It is said that pollenosis is a types of allergic reaction which is mainly induced by allergens present in cedar pollens (the wording "cedar" as referred to in the invention means Cryptomeria japonica and plants of the genus Cedrus), i.e., cedar pollen allergens. The invasion of such an allergen, dispersed in the air, into the body resulted in the formation of immunoglobulin E antibody specific to the allergen. When the body being in such condition is re-invaded by cedar pollens, both cedar pollen allergens contained in the invaded pollens and the already formed immunoglobulin E antibody in the body induce an immunoreaction to cause an allergic symptom.
Until now, it is known that at least 2 different types of allergens with different antigenicities are contained in cedar pollens. The one is an allergen, which is now called "Cry j I", as reported by H. YASUEDA et al. in Journal of Allergy and Clinical Immunology, Vol.71, No.1, Part 1, pp.77-86 (1983), and the other is an allergen, which is now called "Cry j II", as reported by M. TANIAI et al. in FEBS LETTERS, Vol.239, No.2, pp.329-332 (1988) or by M. SAKAGUCHI et al. in Allergy, No.45, pp.309-312 (1990). Usually, cedar pollens contain Cry j I and Cry j II in a weight ratio of about 50:1 to 5:1, and most of the sera collected from patients with pollenosis are said to react with both Cry j I and Cry j II. M. SAWATANI et al. reported in Japanese Journal of Allergology, Vol.42, No.6, pp.738-747 (1993) that Cry j II exerts the same level of antigenicity as that exerted by Cry j I when assayed on the intradermal test (IT) and radioallergosorbent test (RAST).
As described above, several cedar pollen allergens have been isolated and their properties and characteristics have to some extent been assayed. Because of this it may be possible to treat and/or prevent pollenosis by administering to a human a purified preparation of a cedar pollen allergen for desensitization. Recently, desensitization agents for such a purpose have been proposed: For example, Japanese Patent Laid-Open Nos.156,926/89 and 93,730/91 propose a method to administer to a human a conjugate desensitization agent prepared by conjugating a polysaccharide such as pullulan to an allergen having a partial amino acid sequence of Asp-Asn-Pro-Ile-Asp-Ser-(SEQ ID NO:1) or Ala-Ile-Asn-Ile-Phe-Asn-(SEQ ID NO:2) at the N-terminal. Since pollenosis-inducing allergens are not restricted to Cry j I and Cry j II, other pollenosis-related allergens should be urgently isolated and assayed for their properties and characteristics to establish an accurate diagnosis and an effective desensitization-therapy of pollenosis.